As we reported Tuesday, the Mine Safety and Health Administration (MSHA) issued its final report on the cause of the tragedy, echoing earlier findings that placed blame on Massey Energy and what investigators called "systematic, intentional, and aggressive efforts to avoid compliance" with mine safety law.

And the same day, U.S. Attorney Booth Goodwin, said he had reached a settlement with Alpha Natural Resources, the company that bought Massey earlier this year. Goodwin called the $209 million civil and criminal settlement the biggest ever springing from a coal mine disaster.

Briefings about each development were held for the victims' families.

There's more to come.

MSHA is conducting an internal probe of possible agency failures that may have contributed to the tragedy. And a federal criminal investigation continues.

Former MSHA official Tony Oppegard says MSHA's final report underscores the importance of the agency's internal investigation.

"When you read the report [Upper Big Branch] sounds like one of the worst mines in the history of mining," says Oppegard, who now is a mine safety advocate and attorney. "You have an enforcement agency that had to know this was an outlaw operation and they did not use the stringent enforcement tools they had which possibly could have prevented the disaster."

MSHA coal mine safety chief Kevin Stricklin defends his agency's enforcement at Upper Big Branch. "We did shut the mine down 48 times in the year leading up to the explosion," Stricklin notes. "What we don't have is the ability to say because you received so many orders we're going to shut you down permanently."

But the agency failed to place the Upper Big Branch mine on a special "Pattern of Violations" list reserved for repeat offenders and a trigger for heightened scrutiny by regulators. MSHA also didn't use one of its toughest enforcement tools at Upper Big Branch — hauling the mining company into federal court.

Agency officials said this week that the results of their internal investigation are still months away. But Oppegard is skeptical of the probe given an apparent conflict of interest.

"It's hard to imagine that MSHA is going to do a real thorough job, a real critical analysis of itself given the magnitude of this disaster," Oppegard says. "It's just human nature. It's going to be hard to point the finger at your co-workers and say that they did far less than they should have."

Assistant Secretary of Labor Joe Main says MSHA has been investigating itself since 1989.

"I can guarantee you when you go back and look at those reports, there have been a lot of problems that have been found," Main says. "And I think when we issue our [internal] report, it's going be one that's going to identify shortcomings that we need to address."

In addition to that report, Upper Big Branch families are also anxious to see whether the Justice Department will file criminal charges against former Massey Energy executives and managers. Mine disaster prosecutions rarely reach into corporate offices. The only criminal charges filed in the Upper Big Branch investigation so far were not directly related to the mine explosion and involved two low-level officials.

That's what Goodwin may have been referring to Wednesday when he was pressed about possible criminal charges. "Yes," he told reporters, "our investigation has revealed criminal conduct."

Goodwin wouldn't elaborate but he did describe the circumstances at Massey Energy that could lead to indictments of executives if wrongdoing is found.

"Knowledge is a key element," Goodwin explained. "Intent is a key element and when it moves up the ladder all the information doesn't necessarily flow with it."

But then Goodwin noted a documented characteristic of Massey Energy management. "Massey was a company that was fairly closely controlled by a reasonably tight group of individuals."

Criminal charges at the highest levels are important to Gene Jones, a power company engineer whose identical twin Gene was killed at Upper Big Branch.

"I want to see someone actually go to jail," Jones said, after being briefed about the developments this week. "[That will] show these other coal companies, 'Listen. If you do wrong, you're going to go to jail."

"That has to happen," Jones adds, because brothers will continue to die in coal mines until convicted mining executives go to jail.

Goodwin declined to speculate about when the criminal probe might conclude.